In commonly owned U.S. Pat. No. 5,058,747 a container is described that has an annular and erect outer wall in the form of a gridwork of bars having a lower edge and provided at the edge with an annular stiffening bar and a pallet-like floor downwardly closing the wall, forming therewith an outer vessel, and provided with a plurality of wooden foot beams each having a ground-engaging lower surface, an upper surface, and a pair of ends. Respective steel plates on the upper surfaces of the foot beams each have bent-down ends overlying the respective beam ends. Fasteners such as screws or nails are engaged through the steel-plate ends into the respective beam ends. Integral connections are provided between each of the plates and the annular stiffening bar at the lower edge of the wall. An inner vessel composed of flexible plastic material is enclosed by the outer wall and supported on the floor.
This system is an improvement on that described in commonly owned U.S. Pat. No. 5,050,765 which has an outer side comprised of a plurality of vertical flat panels each formed by a gridwork of horizontal and vertical bars with the horizontal bars being interconnected with the panels forming an upwardly open rectangular-section tube. A generally rectangular bottom formed as a gridwork of horizontal bars has respective sides juxtaposed with the panels of the side and the vertical bars of the side have horizontally bent lower ends lying against respective bars of the bottom with at least some of the bent lower ends of adjacent panels of the side crossing one another. An inner vessel composed of a plastic material is enclosed by the outer side and supported on the bottom and respective welds secure together the crossing lower ends of the side and also secure the lower ends and the bars of the bottom together.
These systems are relatively efficient, allowing liquids or bulk fluent materials to be handled easily like normal solid freight. Nonetheless the containers are fairly difficult to manufacture and the critical joint region between the side walls and floors represents a particular problem, as this area is very heavily stressed in use. The system with wooden pallet feet is extremely stiff and vibration- and deformation resistant, but the feet tend to disintegrate fairly rapidly. The wholly metal system, even when it has integral metal feet, is extremely durable, but deforms somewhat easily and is not vibration resistant.